The evolution of the NFL:
Take a look at how the NFL has evolved from its humble roots, and the efforts being made to ensure it continues to grow.

Veteran safety Ryan Clark of the Pittsburgh Steelers told ESPN's "Outside the Lines" on Sunday that it will be difficult for the league to police the rule.

"I think it's going to be really tough to legislate this rule, to find a way to penalize everyone who uses this word," Clark said, according to ESPN.com. "And it's not going to be white players using it toward black players. Most of the time you hear it, it's black players using the word."

As evidence for his take, Clark cited an effort by Steelers chairman Dan Rooney to weed the word out of the Pittsburgh locker room.

"Mr. Rooney actually talked to Ike Taylor about it this season. Ike and Mr. Rooney have a very good relationship," Clark said, per ProFootballTalk. "He told Ike, 'I don't want you guys using that word.'"

Clark said the respect the players have for Rooney led to an immediate acceptance of the request.

"Ike went around to specific people and said, 'Listen, this is what Mr. Rooney told me,'" Clark said. "He's the ambassador. We call him Old Man Rooney. He has a lot of respect, and because of the way he has treated us as players, as black athletes, (and) also treated Coach Tomlin as a black coach, you know it's coming from a place of love."

However, it didn't last.

"You stopped hearing it immediately that day," Clark said. "But after a while, it came back because it's the culture. After a while, it comes back because this is what these guys have grown up with."

Clark's point: The proposed rule might be a good idea, but it could prove difficult to regulate.